Over the years I have noticed that the best gardeners I know are all passionate about their soil. Whether it is Peter Cundall looking lovingly at a handful of good soil muttering sweet nothings like “……..so good you could eat it”, or Lolo Houbein author of One Magic Square and Outside the Magic Square, or any number of other equally good but lesser known great gardeners. There was a direct correlation between their passion for their earth and their gardening prowess – it is no coincidence.
The United Nations Food and Agriculture Organization has named 2015 the International Year of Soils as they recognise that healthy soils are the foundation for our food, fuel, fibre and medicine. So it is fitting that we remember in our own gardens that healthy soil is essential. One of the first things that we must all do to fall in love with our soil is to realize that our soil is brimming with life, whether we can see it or not as at least one quarter of the world’s biodiversity lives underground.
Alive and Well
Worms are one obvious indicator of this life and gardeners also know that they are an indicator of soil health. Earthworms are remarkable, living for up to 8 years and processing up to 30 tonnes of earth in their lifetime. One important job of these tireless workers is to help break down organic matter, and then mix it through the soil to improve its structure and texture. This helps improve water penetration and retention in the soil, and helps improve soil aeration. Worms also increase the availability of nutrients in the soil, as well as help to increase the activity of the soil microbes. This improvement in soil health results in improved plant growth.
As well as the earthworms, it is the tiny microscopic creatures, bacteria and fungi, which are equally important although often misunderstood. In 1 teaspoon of healthy, organic enriched soil there are supposedly 1 million bacteria and 100,000 mycorrhiza or fungi. What do these tiny creatures do? The beneficial bacteria in soil help to break down soil borne pathogens and pollutants, and they also help to sequester atmospheric carbon dioxide. This last one is very profound. The mycorrhiza have many functions but one important one is that they extend the root system of our plants by a ‘surrogate ‘ root system which gives our plants far greater access to moisture and nutrients.
For those that are troubled by the sinister sound of the words bacteria and fungi be reassured that our world would not function without microbes, in fact without the five million-trillion-trillion microbes which live here. In fact, every person has more than 10 times as many microbes living on and inside his or her body as they have human cells. As an example of this each adult has up to 1.5 kg of bacteria in our guts which helps us to function properly and there are 1000 helpful bacteria for everyone one that is harmful to us.
One of these microbes currently being studied further is Mycobacterium vaccae, a natural soil bacterium has been found to triggers the release of serotonin, helping to elevate mood and decrease anxiety. Many gardeners may have said or heard others say “I feel so good when I get my hands in the soil” – now you know why! This same bacterium has been found to improve cognitive function and the ability to learn new tasks, and is currently being studied further as it may be able to help with the treatment of cancer and other diseases.
Feed Your Soil
So what can we do to make sure we have got lots of worms and microbes in our soil? Add organic matter (compost, aged animal manures or anything that was once living) to the soil and think about anything which you put on your soil – is it going to feed the soil life or kill it? Synthetic chemical based fertilizers and soil additives such as soil wetters are harmful to the soil flora while organic fertilizers and plant tonics feed the soil life. Mulching over the warmer weather is also important as it keeps the soil cool and lets these creatures live on whereas worms will disappear from soil which is hot dry and bakes.
Soil is ‘the lungs of the earth’ ………….so fall in love with your soil and you will have a great garden!
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